1. Field of the Invention
The present invention relates to a water-based dispersion ink for a bubble jet recording system using disperse dyes or pigments, and an ink-jet recording method and an apparatus using the ink. More particularly, the present invention relates to a water-based dispersion ink which has a superior dispersion stability in a fine particle, state of disperse dyes or pigments with an average particle size ranging from 0.08 to 1 .mu.m and also has superior ejection properties in, especially, ink-jet recording apparatus based on the bubble jet printing, as well as an ink-jet recording method and an apparatus using the ink.
2. Related Background Art
Recently, water-based pigment dispersions have been used as an ink for writing implements and ink-jet recording apparatus. However, in a system designed to make recording based on the principles that a large amount of heat is directly applied to an ink in a moment to boil the ink itself for forming droplets and also providing ejection energy, such as a bubble jet printing system, it is very difficult to practice printing by employing, as an ink, conventional dispersions as they are. The reason is that, since an ink itself is bubbled on a heating element (heater) of a recording head, the dispersion is thermally destroyed and aggregated to precipitate deposits on the heater, which remarkably reduce the efficiency of bubbling of the ink in subsequent steps.
Therefore, any of means to suppress aggregation of the dispersion, or materials or devices enabling ink ejection to be continued has been required even when the dispersions will be aggregated. In particular, for disperse dyes or organic pigments, it has been difficult to obtain fine particles with the mean particle size of 0.2 .mu.m or less in techniques per se, and limitations have been encountered in a particle size attainable from an industrial point of view. Accordingly, there has been demanded for development of a dispersion technique that can efficiently disperse fine particles having the mean particle size in the range of from 0.08 to 1 .mu.m, and can provide a dispersion having a high stability for preservation and being adaptable for an ejection stability in bubble jet recording apparatus, i.e., being able to respond to a driving frequency at a range of from 3 kHz to 8 kHz.
As the prior art in relation to the present invention, applications of dispersions of water-based pigments to an ink-jet recording ink are disclosed in Japanese Patent Application Laid-Open No. 62-116678, No. 2-255875, No. 1-301760, No. 4-334870, and No. 4-18467. In these disclosed inventions, however, no descriptions are found on not only the problems of fine particle dispersion of organic pigments and ejection properties of the organic pigments in the bubble jet system, but also means for solving the problems. Further, with regard to fine particle dispersion of disperse dyes for use in the bubble jet system, techniques capable of meeting the above-mentioned requirements, i.e., stability of dispersion for a long term and ejection-continuing properties necessary for the bubble jet system, and applications of the techniques are not almost known.
Meanwhile, with regard to a water-based dispersion of disperse dyes, Japanese Patent Application Laid-Open No. 55-54353 can be cited as disclosing the prior art in relation to the present invention. This invention is featured in that phosphated alkylphenolethoxylate in an amount of from 1 to 100% by weight is contained for a weight of dye. As per the laid-opened publication, a crystal growth of a dye molecule in a dispersing medium can be suppressed. With the technique of the disclosed invention, however, it is impossible to obtain a dispersion of fine particles having an average particle size in the range of from 0.08 to 1 .mu.m for use as an ink for an ink-jet recording system and, especially, to achieve satisfactory ejection properties in the bubble jet system.